Revision as of 21:21, 14 March 2013

We often have to use measurements in Wikitravel — for the distances between places, for the altitude of mountains, for the temperature of deserts, for the volume of a glass of beer. This style guideline explains how to specify and format measurements.

Use local units of measurement

When showing a measurement, use the local system of units for the destination you're describing. This is the system that travellers will see on road signs, local maps, menus, food packages, weather reports, etc.

For most of the world, this is the metric system (SI).

However, for the United States of America, it's the "US standard" system of units—similar to, but certainly not the same as, the imperial system of the United Kingdom. In some cases, the systems are mixed—for example, in the UK, road distances are measured in miles and beer served by the pint, while meat and canned goods are measured in (kilo)grams. Milk is measured in both pints (in England and Wales) and litres (in Scotland). We favour accuracy over consistency.

The chief difference between the US system of units and the imperial system is in the sizes of the pint and the gallon. The US measures are 20% smaller than the imperial measures. That means you get more drunk on a British pint, and you get fewer miles to the gallon on American roads!

If the measurements span multiple countries, use metric.

For articles that don't deal with a particular destination (like most travel topics), use metric.

Provide conversions

It's easier for travellers to understand measurements if they're converted to their own country's units. For this reason, it's best to provide conversions for measurements into both metric (SI) and US styles, the two systems most widely used in the English-speaking world.

If the preferred units are metric, try to provide US style measurements in parentheses after. If the preferred units are US Standard, always provide metric measurements in parentheses afterwards.

If for some reason the local unit is neither metric nor US, try to provide first metric, then US (separated by a comma and a space) enclosed in the same parentheses afterwards.

Don't repeat conversions unnecessarily.

Accuracy

There is no need to convert between units to unnecessarily precise decimal places. If you convert between units only state the conversion to the same number of significant digits as the original measure. If you want to show decimal places or be more accurate than a single unit allows, consider going down to a smaller unit. Remember, these measurements are going to be used by travellers, not scientists.

To indicate approximately, use the un-italicised abbreviation "c. " (followed by a space) rather than circa, ca., or approx.

To avoid the unit of measurement that "belongs" to a measurement being "orphaned" from its associated unit when it wraps to a following line, separate the pair with a non breaking space character "&nbsp;" rather than a simple space.

eg:"4500&nbsp;km" will display as 4500 km

Decimal point and commas

In this, the English language version of Wikitravel, a full stop or period should be used to separate any decimal fraction of a number from the integer part and never a comma, whatever the local practice is.

Similarly, don't use a full stop or period as the delimiter to separate groups of three numerals left of the decimal point. Use a comma for this instead.